Default language home page

If you are using the option "Switch by hostname", you should disable all the
others switching options, except the first "Redirect the front page".

can not detect language from browser both firefox and IE
some of $_SERVER["HTTP_ACCEPT_LANGUAGE"] is more then "2" character such like zh-tw, zh-cn
and IE usually only one ["HTTP_ACCEPT_LANGUAGE"] not array() such like "zh-tw"
and firefox HTTP_ACCEPT_LANGUAGE is "zh-tw,en-us;q=0.7,en;q=0.3"
both IE and firefox in HTTP_ACCEPT_LANGUAGE language is the first one,
so maybe use split or preg_match function can do same thing better. :)

1. use preg_match(), $lang is correctly language code, like "en", "jp", "zh-tw","zh-cn"...
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preg_match('/^([a-z-]+)/i', $_SERVER['HTTP_ACCEPT_LANGUAGE'], $matches);
$lang = $matches[1];

----------------------------------------------------------------------------

2. use split(), $language[0] is the first language code
----------------------------------------------------------------------------

$language = split(",", $_SERVER['HTTP_ACCEPT_LANGUAGE'] );
print ($language[0]);

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in localizer.module
--------------------------------------------------------------------
/**
* Get the language of the browser
*/
function localizer_get_browser_lang() {
$languages = localizer_available_uilocales();
$exploded_server = explode(";",$_SERVER["HTTP_ACCEPT_LANGUAGE"]);
$accept=explode(',',array_shift($exploded_server)); ;
foreach ($accept as $lang) {
$lang=substr($lang,0,2);
if (!empty($lang) && array_key_exists($lang,$languages)) {
return $lang;
}
}
return localizer_get_defaultuilocale();
}
------------------------------------------------------------------------

/**
* Get the language of the browser
*/
function localizer_get_browser_lang() {
  $languages = localizer_available_uilocales();
  //$exploded_server = explode(";",$_SERVER["HTTP_ACCEPT_LANGUAGE"]);
  //$accept=explode(',',array_shift($exploded_server));  ;
  //foreach ($accept as $lang) {
  //  $lang=substr($lang,0,2);
    $lang = split(",", $_SERVER['HTTP_ACCEPT_LANGUAGE'] );
    if (!empty($lang[0]) && array_key_exists($lang[0],$languages)) {
      return $lang[0];
    }
  //}
  return localizer_get_defaultuilocale();
}

Many thanks.
I'll integrate your fix.

Thanks Roberto Gerola too, Localizer is a very powerful drupal module,

upload zh-hant's(zh-tw) flag png file,
could be use in localizer\flags\
;)

Fixed